As regards low tuning, I had the jack version, which is as far as i can see identical apart from having a guitar shape body.. I used this in a band down tuned, with my lowest string down to C, these were normal strings not bottom 4 of a 5 string set, and worked absolutely fine like that, for me anyhow.
Assuming it's the same bass apart from body shape, which to me looks to be the case, it will be an excellent instrument, with a great range of sounds, I also regretted selling my Hohner headless.